Effect of crop residue icorporation on management of zinc uptake by wheat plants in a calcareous soil

Limited awareness is available on the effect of preceding crop on phytoavailability of zinc (Zn) in soil. This pot experiment examined the effect of four preceding crops including clover, sunflower, safflower, and sorghum residues on shoot and grain Zn uptake by two wheat genotypes differing in Zn deficiency tolerance, Back Cross and Kavir, in a calcareous Zn-deficient soil. Incorporation of all preceding crop residues into the soil significantly increased organic matter content, dissolved organic C (DOC) and Diethylene Triamine Pentaacetic Acid (DTPA) extractable Zn concentration in the soil. Residues of safflower and clover had the greatest effect on increasing soil DOC. Shoot and grain Zn concentrations were increased by incorporating all pre-crop residues into the soil although this increase was greater in safflower and clover treatments. Incorporation of sorghum residues into the soil had a negative effect on shoot and grain dry matter yield of wheat. Incorporation of safflower and clover residues into the soil increased Zn uptake by wheat shoot and grain. There was a positive significant correlation between shoot and grain Zn concentrations with DOC in soil solution. It shows that DOC, produced from crop residue decomposition, has facilitated Zn uptake by roots of wheat plants and particularly its transfer to grains.